Several different types of disposable injection syringes are known to the art. A disposable liquid-injection syringe is described in relative detail in International Patent Publication WO89/04677, in which the means used to connect and disconnect the piston and rod of the syringe have the form of screw-like means. The International Patent Publication includes exemplifying embodiments of rod and piston connecting means, where the embodiments illustrated in FIGS. 6 and 9 can be said to represent the closest prior art.
Other types of disposable injection syringes are also known to the art, for instance the syringe described and illustrated in Swedish prior Patent Publication SE-B-7902138-2, Publication No. 438,598.
The injection syringe described and illustrated in European Patent Application EP-A-2,229,017 also forms part of the prior art.
The rod configuration illustrated and defined in FIG. 7 of prior Patent Publication U.S. Pat. No. 5,004,460 also belongs to the prior art.
In addition to what is known from the aforecited publications, mention can be made to the different piston-unit and rod-unit connecting means illustrated and defined in prior publications U.S. Pat. No. 4,906,231 and FR-A-2,381,527 and NO-A-163,263.
The inventive syringe assembly is a development of the disposable syringe and the structural components illustrated and described in International Patent Application PCT/SE92/00258 filed on 21st Apr., 1992, and the reader is referred to this document for a closer understanding of the construction and forms of the rod-unit and piston-unit used in the present case and illustrated in the present Application.